Such seals are used for the releasable, fluid-tight attachment of housings, such as oil pans or valve covers, on the engine block, or for covers of crankshaft and gear housings. When sealing a crankshaft housing, the housing cover consists of a dynamic seal for the crankshaft extending through the cover, whereby the dynamic seal consists of at least one, possibly spring-loaded, elastic sealing lip that has been attached by vulcanization, as well as two flange surfaces that meet each other at an angle of usually 90 degrees and that must be statically sealed, and of which one extends radially to the crankshaft housing and is used for the tight connection with the crankshaft housing, and the other extends in the crankshaft axial direction and is provided for the tight connection with the oil pan, whereby sealing strips that project from the flange surfaces are provided for the static sealing of both flange surfaces in the crankshaft axial direction or radially in relation to it.
DE-PS 36 34 735 introduces a housing cover consisting of a sheet metal body drawn in bowl shape which, for the purpose of sealing the crankshaft, is provided with a dynamically loaded sealing ring of an elastomer material, as well as statically acting sealing strips, also made from an elastomer material, which merge with each other to form one piece. A sealing strip exiting from the axial flange surface is used for sealing the oil pan which can be screwed in from the bottom against the crankshaft housing. Two nuts are welded into the housing cover so that during the unscrewing of the oil pan the sealing strip between the housing cover and the oil pan can be pressed together with an adequate superficial pressure in order to create the seal.
A flawless seal requires that the surfaces of the housing surfaces opposite from the sealing strip are highly accurate, which has a great effect on manufacturing and processing costs. Special requirements for a perfect seal are hereby posed not only by the macro-irregularities of the surfaces, but also by micro-roughnesses, pores, step transitions, etc. In addition, heat fissures and furrows may occur over time on the sealing strips during operation, which may result in a long-term deterioration of the sealing effect.